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<head>
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    <title>Document</title>
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<body>
    <script>
        var arr = ["html", "css", "js"];
        for (let key in arr) {
            console.log(key)
        }
        for (let val of arr) {
            console.log(val);
        }
        var attr = [
            { type: "string", key: "name", value: "xzd" },
            { type: "int", key: "length", value: 1000 },
        ]
        // var values = ['xzd', 1000]
        var values = attr.map(item=>item.value);
        console.log(values);
    </script>
</body>

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